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TROPICAL DEPRESSION KATRINA DISCUSSION NUMBER 12
NATIONAL WEATHER SERVICE MIAMI FL
10 AM EST SUN OCT 31 1999
SATELLITE IMAGERY AND LIMITED SURFACE OBSERVATIONS FROM THE YUCATAN
PENINSULA SUGGESTS THAT THE ILL-DEFINED CENTER OF KATRINA IS OVER
THE SOUTHEAST PORTION OF THE PENINSULA. THE BEST ESTIMATE OF THE
INITIAL MOTION IS 345/09 KNOTS.
THE INITIAL INTENSITY IS HELD AT 25 KNOTS. GRADUAL STRENGTHENING
IS INDICATED THROUGH 36 HOURS AS THE SYSTEM EMERGES INTO THE CENTRAL
GULF OF MEXICO ALTHOUGH THIS IS HIGHLY DEPENDANT ON THE TRACK. THE
INTENSITY FORECAST FROM THE PREVIOUS ADVISORY HAS BEEN MAINTAINED
DUE TO THE UNCERTAINLY IN THE FORECAST TRACK. THE BEST CHANCE FOR
KATRINA TO REACH AND MAINTAIN TROPICAL STORM INTENSITY WILL BE ON
A MORE EASTERLY TRACK WHERE A MORE FAVORABLE SHEAR ENVIRONMENT IS
LIKELY TO EXISTS. KATRINA IS FORECAST BECOME EXTRATROPICAL BY 72
HOURS AS IT MERGES WITH...OR IS ABSORBED BY...THE FRONTAL SYSTEM
APPROACHING FROM THE WEST.
THE FUTURE TRACK OF KATRINA IS HINGED ON THE DEEP-LAYER TROUGH
OVER TEXAS AND ASSOCIATED FRONTAL SYSTEM. BASED ON BOTH THE INITIAL
POSITION AND ON THE 12Z TRACK GUIDANCE...WHERE ONLY LBAR SHOWS A
MORE WESTERN TRACK AND MOVES THE SYSTEM INTO THE EASTERN FLORIDA
PANHANDLE AFTER 36 HOURS...THE OFFICIAL FORECAST TRACK HAS BEEN
SHIFTED TO THE RIGHT OF THE PREVIOUS ADVISORY. IT SHOULD BE
EMPHASIZED THAT THERE IS CONSIDERABLE UNCERTAINTY IN THE LATTER
PORTION OF THIS TRACK. BASED ON THE PROJECT TRACK SCENARIO A
TROPICAL STORM WATCH MAY BE REQUIRED FOR PORTIONS OF THE WEST
FLORIDA COAST LATER TODAY OR TONIGHT. ALL INTERESTS ELSEWHERE
IN FLORIDA...AND IN THE CENTRAL AND EASTERN GULF OF MEXICO SHOULD
CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM.
GUINEY
FORECAST POSITIONS AND MAX WINDS
INITIAL 31/1500Z 19.3N 88.2W 25 KTS
12HR VT 01/0000Z 21.6N 88.3W 30 KTS
24HR VT 01/1200Z 25.0N 87.3W 35 KTS
36HR VT 02/0000Z 28.0N 84.5W 40 KTS
48HR VT 02/1200Z 31.0N 79.5W 40 KTS
72HR VT 03/1200Z 37.0N 70.0W 40 KTS...EXTRATROPICAL
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